Sedums are succulents and will not take a lot of foot traffic without being crushed - I'm not sure where anyone got the idea they thrive on it. It would be suited to an herb bed, as it is very low growing and will like much of the same conditions - full sun and rather dry soils. It would not be very effective in smothering out grass as it doesn't spread thickly or rapidly enough and the grass easily grows through it.

Thank you so much for the info!